The invention relates to instruments used in bone preparation and implant trial reduction during joint arthroplasty procedures. More particularly, the invention relates to modular instruments used to prepare the tibia to accept a prosthetic tibial tray, and to instruments useful as trial tibial trays.
Joint arthroplasty procedures in which a diseased and/or damaged natural joint is replaced with a joint prosthesis are well known. Among the more common joint arthroplasty procedures are those that involve replacement of knee joints and hip joints.
Knee arthroplasty is a surgical procedure by which a diseased and/or damaged natural knee joint is replaced with a prosthetic knee joint. A typical total knee prosthesis includes a femoral component, a patella component, a tibial tray or plateau, and a tibial bearing insert. The femoral component generally includes a pair of laterally spaced apart condylar portions, the distal surfaces of which articulate with complementary condylar elements formed in a tibial bearing insert. The tibial tray is mounted within the tibia of a patient. Tibial trays typically include a keel or stem extending from the inferior surface thereof. This keel or stem can be implanted within a prepared cavity of the tibia that is formed during the surgical procedure. The tibial tray is secured to the tibia by bone cement and/or by press fit fixation techniques. The tibial bearing insert is typically affixed to the superior surface of the tibial tray.
During the course of a joint arthroplasty procedure, surgeons must evaluate the size and condition of the patient's bones (e.g., the tibia) that will accept a component of the joint prosthesis. In addition, the affected bones must be prepared to receive the prosthesis components. Bone preparation and the choice of the appropriate prosthesis components are factors which significantly influence the success of a joint arthroplasty procedure. Obviously, the bone preparation procedures are tedious and time consuming.
Once a bone has been properly prepared to accept a prosthesis component, surgeons typically utilize a "trial" system of prosthesis components that are provided by the prosthesis manufacturer. The trial components are sample prosthesis components, available in various sizes and shapes, that are intended to be placed into the prepared bone on a temporary basis for evaluation purposes only. Typically, surgeons evaluate a number of different trial components to determine the size and/or shape of a prosthesis component that will best suit a patient's needs.
In many joint arthroplasty procedures separate sets of tools and components are used to prepare the bone and subsequently to evaluate various prosthesis trial components. The use of separate sets of tools and components for these steps in a joint arthroplasty procedure further complicates an already difficult and time consuming process. Many prior art techniques require the removal of all bone preparation components after the bone has been prepared. Subsequently, the trial components are then sampled within the prepared bone.
U.S. Pat. No. 5,628,749 discloses instrumentation useful to prepare the proximal tibia to accept a tibial prosthesis. This instrumentation enables a surgeon to effect all necessary resection and drilling of the femur. When this is accomplished, a tibial trial is placed on the prepared tibia for evaluation of size and fit. Other instruments useful for preparation of the proximal tibia are disclosed in U.S. Pat. No. 4,759,350.
U.S. Pat. No. 5,609,642 discloses a tibial trial and bone preparation system. This system enables a surgeon to place a tibial tray trial on a resected tibia, and to rotate the tray trial to a preferred position. When the preferred position is achieved femoral and tibial trials are allowed to articulate with each other through the full range of motion of the knee. The trial tibial bearing insert is then removed from the trial tibial tray and the tibia is further prepared using a fin punch.